Use of small biometric sensors, i.e. sensors that do not collect biometric data about the whole biometric object, may be desired due to constraints caused by e.g. physical design of an apparatus used to collect the biometric data. Use of such small biometric sensors may also cause a problem where earlier collected biometric data for a biometric template and collected biometric data for matching to the template do not overlap enough for a proper matching. An approach to alleviate this is to use multiple biometric readings for the template wherein likelihood for overlap increases. An approach is to store a large amount of templates. However, this approach not only requires large memory space, but also increases complexity in choosing the template to match with. It is therefore a desire to handle such multiple templates efficiently.